Various surgical operations require access to an inner body cavity of a patient through a cannula. For example, in arthroscopy and laparoscopy, a cannula can be used to provide access to various surgical sites in joints and/or cavities, allowing surgical instruments, sutures, and various other surgical tools to be passed through the cannula. A cannula can also be used to provide positive air and/or water pressure at the surgical site without losing access to the surgical site through use of various seals, such as deformable dams.
While adding seals to the cannula allows pressure to be maintained, the seals can restrict access to various tools through the cannula because the seals can obstruct part or all of the cannula. Various removable dams can be used, but insertion and placement of the dams can cause problems. For example, if sutures extend from a body cavity and out of a cannula, introducing a removable dam to the cannula would either pinch the sutures or require a surgeon to introduce the sutures through an opening in the dam, causing a loss of time and effort during surgery.
Accordingly, there remains a need for improved methods, systems, and devices for allowing surgical instruments to access a body cavity through a cannula.